28 December // Monday
Making vocab index cards for Malay. I’m somehow determined to get better at it next year after studying (and doing badly at) it for the past 8 years. It’s never too late to change!! 😬

Ganymede and Callisto are similar in size and are made of a similar mixture of ice and rock, but data from theGalileo and Voyager spacecraft show that they look different at the surface and on the inside. Just like Earth and Venus, Ganymede and Callisto are twins, and understanding how they were born the same and grew up to be so different is of tremendous interest to planetary scientists.

Ganymede and Callisto’s evolutionary paths diverged about 3.8 billion years ago during the Late Heavy Bombardment, the phase in lunar history dominated by large impact events. Impacts during this period melted Ganymede so thoroughly and deeply that the heat could not be quickly removed. All of Ganymede’s rock sank to its center the same way that all the chocolate chips sink to the bottom of a melted carton of ice cream. Callisto received fewer impacts at lower velocities and avoided complete melting. Ganymede is closer to Jupiter and therefore is hit by twice as many icy impactors as Callisto, and the impactors hitting Ganymede have a higher average velocity.

Ever since Galileo first turned his telescope to Jupiter back in 1610, we’ve been marvelling at the monstrous planet. We’ve been captivated by its sheer size (so big it can fit 1,300 Earths inside), its moons (all 67 of them), its incredible magnetic field (which creates shimmering auroras at the poles) and its swirling storms - including the Great Red Spot, which has been raging for more than 300 years.

In mythology, Jupiter was the king of the Roman gods, and the goddess Juno was his wife. In one story, Jupiter draws a veil of clouds around himself to hide his mischief - and Juno was the only person who was able to peer through the clouds and see Jupiter’s true nature. Like its namesake, NASA’s Juno spacecraft will help us unlock the mysteries beneath the giant gas planet’s thick clouds.

After travelling 2.8 billion kilometres over the past five years, Juno will arrive late Monday night and will spend nearly two years orbiting the giant gas planet. Powered by solar panels each the size of a bus, Juno will study Jupiter’s atmosphere, finding out far the clouds and storms go down - are they just a thin layer, or do they go all the way down to the planet’s core? And what’s the core made of? Is it metallic hydrogen, or rock, or heavy metal, or something we haven’t even thought of?

Juno will also help us study the formation of Jupiter and indeed the formation of the whole solar system. We know that Jupiter is made up of hydrogen and helium gas, like the Sun, but it also contains a higher proportion of heavier elements and we’re currently not sure why. Learning more about what Jupiter’s composition will help us figure out how it formed, over four billions of years ago when our sun was was newborn. This in turn will help us understand the formation and evolution planetary systems we’re discovering around distant stars.

Juno will also study the Great Red Spot, measure the water in the atmosphere, and study the enormously strong magnetic fields and how they create Jupiter’s auroras.

But Jupiter is a dangerous neighbourhood to explore. The intense magnetic field creates a radiation belt around the planet, made up of super energetic particles. Even though Juno is equipped with titanium vault to protect its scientific equipment, eventually the radiation will fry the spacecraft’s electronics. Then, NASA scientists will direct Juno to plunge into the clouds of Jupiter, where it will break apart and melt.

But two years are a long time to explore the enigmas beneath the swirling clouds of Jupiter - and Juno is sure to answer many of our burning questions.

Cas exhaled. “When an angel’s wings are injured,” he said to his feet, “the healing process can be augmented by… grooming, I suppose, would be the most accurate word. Removal of the maimed feathers to allow growth of healthy ones. Otherwise, they’re left to fall out alone.” He tilted his head towards the nightstand. “As you see." Dean stared at him. "So… that’s why I can’t help?” he said slowly. “‘Cause I can’t, y'know… see 'em? Or touch 'em?" "Yes,” Cas said, slightly too quickly, and Dean snorted.“You’re still a shitty liar, Cas,” he informed him. “What ain’t you tellin’ me?”

It’s like a drug, this magical wardrobe, a compulsion. Four universes, he’s seen now. Four Deans who love him, who’ll kiss him when his own will not. And he doesn’t know if they’re real, if these universes truly exist somewhere out there, or if they’re just showing him what he wants to see but he’s not even sure he really cares. He takes a shaky breath and climbs through again.

He’s about to put the receipt down, no harm done, when something about it catches his eye. Pen ink, on the back. He flips it around and reads: With Dean. He shared his pie with me. His smile was radiant. Dean stares. Reads it again. Nothing’s changed. What?

It starts because they need a rock. Not, of course, just any rock, but apparently this particular critter needs an Aztec-style obsidian-and-jade dagger right through its human-teeth-and-eyeball-eating heart to actually kill it. In which Cas gets a ring, and Dean (finally) gets a clue.

“Y’all are sweet,” she says, and nods to indicate him and Cas. “Is he your—are you all together?” Dean’s still contemplating how to answer this without saying something offensive—he never has figured out a polite way to say “no homo”—when Cas answers for him. Cas doesn’t even look up from his plate, his mouth full of baklava and some stray flakes of phyllo dough sticking to his lips when he says, “Yes.” Dean feels more than sees Sam go very still across the table, forkful of salad and grilled chicken poised in midair. In which Cas is human and doesn’t understand basic concepts like: clothing, Mythbusters, moisturizer, and Greek food. Dean is…Dean and doesn’t understand basic concepts like: boyfriends, language, how to tell your friend that he’s a walking miracle, and when not to quip.

Dean plays another game of are we dating or do we just fuck sometimes? The game goes like this, drink a bottle of beer for every maybe-date he’s been on with Cas and drink a double shot for every time they’ve fucked. Dean’s not sure if it’s a good thing or a bad thing that he’s been stumbling drunk for the last four days.

Sam slammed his hand down on the table, making Dean and Cas both jump. “I don’t buy it.” “What?” Dean asked, acting wholly innocent, while Cas just tipped his head and squinted at Sam, like they honestly hadn’t noticed this was going on. “This whole marriage thing. No one gets accidentally married, and if they did, it’s in Vegas and there’s a divorce right after.” “You should know,” Dean snorted.